Userpicker can't find admin

When users on my site want to send me a message, they can't just go to messages > create a message, because the userpicker can't find my name. If they click on my avatar and choose send a message, then my name will be placed as the recipient.

I've been wondering if it might be because I'm a creator of the site or admin. Has anyone experienced this?

Elgg 3.1.1